For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningInstallation Procedure
Create 8 x 14 mm (5/16 x 15/16 in) slots for MIG-Brazing along the edges
of the drivetrain and front suspension frame front support
as noted from the original panel.
Clean and prepare the attaching surfaces for brazing.
Position the drivetrain and front suspension frame ...
Removal Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in the
Preface section.
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface section.
Disable the SIR System. Refer to SIR Disabling
and Enabling.
Disconnect the negative battery cable. Refer to ...
Installation Procedure
Align the rear side door outer panel.
Verify the fit of the rear side door outer panel.
Clamp the rear side door outer panel
into position.
Pre-flanging the flange with BO-6396 pliers and BO-6392 tool kit .
Continue to hammer in stages along the hem flanges.
App ...